A prior art wrapped-card assembly for a GSM telephone service comprises a wrapping and enclosed therein a data encoded card and an auxiliary card. The data-encoded card comprises a subscriber identity module (“SIM”)for accessing the GSM telephone service. The auxiliary card comprises confidential and non-confidential information in a printed form. The confidential information comprises two secret codes needed to access the GSM telephone services, namely a personal identification number (“PIN”) and a personal unblocking key (“PUK”). The PIN and the PUK are covered by a non-transparent scratch material. The confidential information remains therefore non readable until an end-user opens the wrapping and subsequently removes the scratch material. The non-confidential information is readable through the wrapping. It can be, for example, a magnetic strip, a laser strip or a code bar containing all the information related to the manufacturing process such as, for example, an identification number or the price. In a matching step, for each data-encoded card the corresponding auxiliary card is selected. The data-encoded card and the corresponding auxiliary card are wrapped into a single wrapping. The wrapping can be made of a transparent material.